Copy of In E. coli, fatty acids (CH 3 -(CH 2 ) n -COOH) with an even number of c
ID: 206506 • Letter: C
Question
Copy of
In E. coli, fatty acids (CH3-(CH2)n-COOH) with an even number of carbons are degraded to acetate by the removal of one 2 carbon unit (acetate) at a time according to the reaction:
(CH3-(CH2)n-COOH) + FAD + NAD+ <--> (CH3-(CH2)n-2-COOH) +FADH2 + NADH + acetate (CH3COOH)
The acetate is then broken down to CO2 and H2O by the usual pathway of energy metabolism. (For this problem consider acetate to be equivalent to acetyl CoA. (This is a simplification.)
If your energy metabolism is the same as E. coli's, which generates more usable energy, one gram of glucose (MW = 180 g/mole) or 1 gram of fatty acid with 6 carbons? (Think! You don't need a lot of calculations to answer.)
glucose
fatty acid
equally fattening.
xxx only 3 to choose from xxxx
glucose
fatty acid
equally fattening.
xxx only 3 to choose from xxxx
Explanation / Answer
Carbohydrates yield energy of 4 calories per gram while fats yield 9 calories per gram. Even in biochemical aspects, 6 carbon fatty acid yields more energy than 6 carbons glucose. This is because fatty acids contain double bonds that produce moe energy when they are hydrolysed. option 2 is correct.